Quasi-solid-state electrolyte composite based on three-dimensionally ordered macroporous metal-organic framework materials for lithium secondary battery and method for manufacturing the same

ABSTRACT

A three-dimensionally ordered macroporous (3DOM) metal-organic framework material (MOF)-based quasi-solid-state electrolyte thin film for a safe quasi-solid-state lithium secondary battery are involved in present invention. In detail, the above quasi-solid-state electrolyte combines 3DOM-MOFs and the electrolytes like polymer and traditional liquid electrolyte. The special pore structures in 3DOM-MOFs could both fill the polymer electrolyte and liquid electrolyte with macropores and micropores, respectively. This unique structure could significantly enhance the Li+ conductivity rate through the different kinds of electrolytes in the corresponding pore structures as well as improves the battery performance. More importantly, this quasi-solid-state electrolyte is much safer than the traditional organic electrolyte. It should be easily to scale-up since the procedures are simple.

FIELD OF THE INVENTION

The present invention related to quasi-solid-state electrolyte to composite, energy materials and quasi-solid-state secondary Li battery.

Specifically, the solid electrolyte thin film was composed of three-dimensionally ordered macroporous metal-organic framework materials, polymers and liquid electrolyte.

BACKGROUND OF THE INVENTION

Traditional lithium batteries usually employ the liquid organic electrolytes, and thus bringing the safety issues, like inflammable, liquid leakage and short circuit temperature rise.

The commercialization process of those varies of rechargeable batteries are delayed. To this end, the development of safe and reliable electrolytes is a great challenge.

Among the above novel electrolytes, all-solid-state electrolyte is attacking more and more interests in recent years because of the high safety. However, it prefers to fundamental research as the poor interfacial structure between the electrodes and electrolyte and the low ionic conductivity at room temperature.

Quasi-solid-state electrolyte as a better approach applies a little bit liquid electrolyte, and thus having high safety due to the inflammability and non-leakage. Furthermore, quasi-solid-state electrolyte could be easily assembled with the positive and negative electrodes to obtain a higher capacity. However, the design of a quasi-solid-state electrolyte with high-performance is challenging.

In the above described quasi-solid-state-electrolyte, the formation of any electrolyte materials containing a polymer and liquid electrolyte are proposed. For example, US patent application of US20170179545A1 describes a quasi-solid-state lithium battery with high thermal stability containing a sulfide solid electrolyte material. Furthermore, US20170084949A1 describes a quasi-solid-state electrolyte that has a well-balanced combination of contact performance with electrode active materials, conductivity, and chemical and structural stability, each at a high level, and an all solid-state lithium secondary battery using the quasi-solid-state electrolyte. In addition, China patent application of CN101013766A describes a quasi-solid-state-electrolyte containing ionic liquid and inorganic layer materials. China patent application of CN101752090A describes a quasi-solid-state electrolyte using polyionic liquid and polyvinylidene fluoride.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects existing in the existing battery electrolyte, thereby providing a quasi-solid electrolyte material based on a three-dimensional ordered macroporous (3DOM) metal-organic frame material (MOF) channel compounded with a small amount of a liquid electrolyte and a polymer electrolyte, and a manufacturing process, and uses of the material in lithium ion batteries and lithium sulfur batteries. The solid electrolyte material based on the three-dimensional ordered macroporous metal-organic framework material has excellent stability and safety in lithium ion batteries and lithium sulfur batteries, and has high reproducibility of steps, which is suitable for industrial production.

The object of the present invention and its technical problems are solved by adopting the following technical solutions. A quasi-solid electrolyte for a lithium battery based on a three-dimensional ordered macroporous metal-organic framework material cell composite, according to the present invention, comprises a metal-organic framework material, a polymer electrolyte material, a liquid electrolyte, and a lithium salt. The said metal-organic framework material, polymer electrolyte material, liquid electrolyte, and lithium salt, in terms of weight percentage, the percentage of the three-dimensional ordered to macroporous metal-organic framework material is 10%-70%, preferably 15%-60%; the percentage of the said polymer electrolyte material is 5%-80%, preferably 20%-80%; the percentage of the said liquid electrolyte is 0.01%-1%, preferably 0.5%-1%; and the percentage of the said lithium salt is 5%-19%, preferably 8%-19%.

In one preferable example, the said three-dimensional ordered macroporous metal-organic framework materials are selected one or more from 3DOM-PCN-601, 3DOM-ZIF-8, 3DOM-ZIF-67, 3DOM-ZIF-68, 3DOM-ZIF-69, 3DOM-ZIF-70, 3DOM-ZIF-78, 3DOM-ZIF-81, 3DOM-ZIF-82, 3DOM-ZIF-95, 3DOM-ZIF-100, [{Fe₃(μ₃-O)(bdc)₃}₄{Co₂(na)₄(LT)₂}₃] and JUC-1000.

In one preferable example, the said polymer electrolyte material is selected from one or more of a polyethylene oxide group, a polymethyl methacrylate group, a polyacrylonitrile group, a polyvinylidene fluoride, a polyvinylidene fluoride, and a copolymer of hexafluoropropylene.

In one preferable example, the said polymer electrolyte materials are selected from polyethylene oxide groups, or copolymerization of polyethylene oxide groups with polymethyl methacrylate groups, polyacrylonitrile groups, polyvinylidene fluoride, polyvinylidene fluoride, and hexafluoropropylene. Of any of them.

In one preferable example, the said liquid electrolyte is selected from one or more of tetraethylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethanol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, and methyl ethyl sulfone.

In one preferable example, the said liquid electrolyte is selected one or two from the group consists of tetraethylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethanol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, and methyl ethyl sulfone.

In one preferable example, the said lithium salt is selected from one or more of LiPF₄, LiBF₄, LiClO₄, LiAsF₆, LiBOB, LiODFB, LiCF₃SO₃, LiN(SO₂CF₃)₂.

The object of the present invention and its technical problems are also achieved by adopting the following technical solutions. A method for preparing a quasi-solid electrolyte for a lithium battery based on a three-dimensional ordered macroporous metal-organic frame material channel composite as claimed in the present invention, the method includes the following steps:

(a) Preparation of three-dimensional ordered macroporous metal-organic framework materials;

(b) uniformly mixing the three-dimensional ordered macroporous metal-organic framework material prepared in the above step a with a polymer electrolyte material and a lithium salt according to a certain ratio, and then pressing into a film;

(c) The membrane obtained in the above step b is immersed in a liquid electrolyte and then dried to obtain a lithium battery quasi-solid electrolyte based on a three-dimensional ordered macroporous metal-organic frame material channel composite.

With the above technical solution, the present invention has at least the following advantages:

(1) The three-dimensional ordered macroporous metal-organic framework material of the present invention, that is, 3DOM-MOFs, is a material having a three-dimensional structure, which has both large and small pores, and the channels are uniformly distributed and oriented, Orderly, regular and so on.

(2) The three-dimensional ordered macroporous metal-organic framework material of the present invention, a polymer electrolyte material can be compounded in the macropores, and a small amount of a conventional liquid electrolyte can be compounded in the small holes, and a quasi-solid electrolyte material is obtained after being pressed into a film. No liquid electrolyte leakage, which greatly reduces the content of flammable electrolyte, which can significantly reduce the safety risk of battery electrolyte.

(3) The quasi-solid electrolyte based on the 3DOM-MOFs composite of the present invention has a high ion conduction rate between the electrolyte and the polymer electrolyte in the components, which can significantly enhance the Li+conduction rate, thereby improving lithium ion batteries and lithium sulfur. Battery performance.

(4) The preparation method of the present invention has simple steps and high reproducibility, and is suitable for industrial production.

In summary, the special quasi-solid electrolyte material and its preparation method of the present invention provide a quasi-solid electrolyte material with excellent performance and its preparation method, which is more suitable for practical use and has industrial application value. It has many of the above advantages and practical values, and it is indeed an innovation without similar publication or use in similar preparation methods. It is a great improvement both in preparation method and function. Technically, it has made great progress and produced good and practical effects, and has a number of improved functions over the existing electrolyte materials and their preparation methods, so it is more suitable for practical use, and has extensive industrial use value. Sincerely, A new, progressive and practical new design.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and can be implemented in accordance with the content of the description, the following detailed description of the drawings and preferred embodiments of the present invention is as follows.

The specific preparation method and structure of the present invention are given in detail by the following examples.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is the SEM image of 3DOM-ZIF-67-PEO-LiPF₄/LiBOB in example 1.

FIG. 2 is the SEM image of 3DOM-ZIF-67-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte with higher magnification in example 1.

FIG. 3 is the TEM image of 3DOM-ZIF-67-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte in example 2.

FIG. 4 is the SEM image of 3DOM-ZIF-67/3DOM-ZIF-8-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte with higher magnification in example 3.

FIG. 5 is the EIS results of quasi-solid-state electrolyte resistance in Example 1 and Comparative Example 1 and 3.

FIG. 6 is charge-discharge performance of the quasi-solid-state Li-ion battery in Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, the present invention will be described batteries in more detail based on examples. Meanwhile, the present invention is not interpreted to be limited thereto.

Example 1

I. Production of Quasi-Solid-State Electrolyte

The PS/H₂O solution is centrifugated with the rotation rate of 4000 r/h for 6 hours, and the top clear solution is poured out. The precipitation sample is dried at 90° C. for one night to obtain the ordered PS template. The above PS template is immersed into the cobalt nitrate/methanol solution with the concentration of 0.05 g/mL for 2 hours. Then the solution is removed and the PS template is dried at 90° C. for one night. The above sample is immersed into 2-methylimidazole/methanol solution with the concentration of 0.1 g/mL for 48 hours to obtain PS/ZIF-67 composite. It is immersed into DMF and stirs for 24 hours to remove PS to get the 3DOM-ZIF-67. Weigh 3DOM-ZIF-67, PEO 6 mg and 2 mg, respectively. Weigh LiPF₄ and LiBOB 0.75 mg, 0.75 mg, respectively. The four samples are stirring well and then form a film using the preforming machine.

II. Electrochemical Characterization of the Quasi-Solid-State Electrolyte

The ion conductivity was tested at different temperatures.

III. Production of Li—S all-Solid-State Battery

Such electrolyte was then immersed in 70% S/CS₂ solution at 155° C. for 6 h to obtain carbonaceous fabrics, which were mixed with carbon black (wt. 10%) and PVDF (10%) as the cathode material. Assembling it with Li metal and commercialized Celegard 2500 separator to Li—S battery. The battery performance was then tested at room temperature.

IV. Production of Li-Ion all-Solid-State Battery

The commercialized ternary cathode material of Nickel Cobalt Manganese (NCM523), graphite as the positive and negative electrode, respectively. While the obtained all-solid-state material is used as the electrolyte. The cell is assembled and tested under open air condition.

Example 2

In Example 2, the weight percentage of 3DOM-MOFs in the whole quasi-solid-state electrolyte was adjusted.

I. Production of Quasi-Solid-State Electrolyte

The PS/H₂O solution is centrifugated with the rotation rate of 4000 r/h for 6 hours, and the top clear solution is poured out. The precipitation sample is dried at 90° C. for one night to obtain the ordered PS template. The above PS template is immersed into the cobalt nitrate/methanol solution with the concentration of 0.05 g/mL for 2 hours. Then the solution is removed and the PS template is dried at 90° C. for one night. The above sample is immersed into 2-methylimidazole/methanol solution with the concentration of 0.1 g/mL for 48 hours to obtain PS/ZIF-67 composite. It is immersed into DMF and stirs for 24 hours to remove PS to get the 3DOM-ZIF-67. Weigh 3DOM-ZIF-67, PEO 4.5 mg and 3.5 mg, respectively. Weigh LiPF₄ and LiBOB 0.95 mg, 0.95 mg, respectively. The four samples are stirring well and then form a film using the preforming machine.

III. Electrochemical Characterization of the Quasi-Solid-State Electrolyte

The ion conductivity was tested at different temperatures.

IV. Production of Li—S all-Solid-State Battery

Such electrolyte was then immersed in 70% S/CS₂ solution at 155° C. for 6 h to obtain carbonaceous fabrics, which were mixed with carbon black (wt. 10%) and PVDF (10%) as the cathode material. Assembling it with Li metal and commercialized Celegard 2500 separator to Li—S battery. The battery performance was then tested at room temperature.

V. Production of Li-Ion all-Solid-State Battery>

The commercialized ternary cathode material of Nickel Cobalt Manganese (NCM523), graphite as the positive and negative electrode, respectively. While the obtained all-solid-state material is used as the electrolyte. The cell is assembled and tested under open air condition.

Example 3

In Example 3, the kind number of MOFs in the whole quasi-solid-state electrolyte was adjusted.

I. Production of Quasi-Solid-State Electrolyte

The PS/H₂O solution is centrifugated with the rotation rate of 4000 r/h for 6 hours, and the top clear solution is poured out. The precipitation sample is dried at 90° C. for one night to obtain the ordered PS template. The above PS template is immersed into the cobalt nitrate/methanol solution with the concentration of 0.05 g/mL for 2 hours. Then the solution is removed and the PS template is dried at 90° C. for one night. The above sample is immersed into 2-methylimidazole/methanol solution with the concentration of 0.1 g/mL for 48 hours to obtain PS/ZIF-67 composite. It is immersed into DMF and stirs for 24 hours to remove PS to get the 3DOM-ZIF-67. 3DOM-ZIF-8 is obtained with the similar procedures. Weigh 3DOM-ZIF-67, 3DOM-ZIF-8, PEO 4 mg, 2 mg, 2 mg, respectively. Weigh LiPF₄ and LiBOB 0.75 mg, 0.75 mg, respectively. The above samples are stirring well and then form a film using the preforming machine.

II. Electrochemical Characterization of the Quasi-Solid-State Electrolyte

The ion conductivity was tested at different temperatures.

III. Production of Li—S all-Solid-State Battery

Such electrolyte was then immersed in 70% S/CS₂ solution at 155° C. for 6 h to obtain carbonaceous fabrics, which were mixed with carbon black (wt. 10%) and PVDF (10%) as the cathode material. Assembling it with Li metal and commercialized Celegard 2500 separator to Li—S battery. The battery performance was then tested at room temperature.

IV. Production of Li-Ion all-Solid-State Battery

The commercialized ternary cathode material of Nickel Cobalt Manganese (NCM523), graphite as the positive and negative electrode, respectively. While the obtained all-solid-state material is used as the electrolyte. The cell is assembled and tested under open air condition.

Comparative Example 1

The quasi-solid-state electrolyte is produced in the same manner as in the Example 1 except that the 3DOM-MOFs used in the Example 1 was not used for Li—S battery.

Comparative Example 2

The quasi-solid-state electrolyte is produced in the same manner as in the Example 1 except that the 3DOM-MOFs used in the Example 1 was not used for Li-ion battery.

Comparative Example 3

The CR2032 coin cells were assembled by using sulfur composite (S and Li₂S, 1:1 by mole) electrode as cathode, Celgard 2500 membrane as separator, and lithium foil as anode in Ar-filled glove box with moisture and oxygen level lower than 0.5 ppm. The electrolyte contains 1M lithium bis(trifluoromethane) sulfonamide (LiTFSI) in a binary solvent of dimethoxymethane/1,3-dioxolane (DME/DOL, 1:1 by volume) with 2 wt. % LiNO₃ as additive.

FIG. 1 shows that the 3DOM-ZIF-67-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte in present invention was successfully obtained.

FIG. 2 shows that the pores of 3DOM-ZIF-67-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte in present invention are ordered and the particle size is not so uniform.

The TEM image in FIG. 3 confirms the existence of pores of 3DOM-ZIF-67-PEO-LiPF₄/LiBOB. And some pores are blocked with the PEO, thus it is not so clear to see.

FIG. 4 is the 3DOM-ZIF-67/3DOM-ZIF-8-PEO-LiPF₄/LiBOB quasi-solid-state electrolyte in present invention was successfully obtained.

FIG. 5 shows that the quasi-solid-state electrolyte resistance in Example 1 and Comparative Example 1 and 3 was 87Ω, 125Ω, 162Ω, respectively, indicating that the existence of 3DOM-MOFs particles is beneficial for reducing the resistance and improving the Li⁺ ion conductivity as the PEO crystallinity degree could be lowered by the 3DOM-MOFs.

FIG. 6 shows that the charge-discharge performance of the quasi-solid-state Li-ion battery in Example 1 still reaches 151 mAh even after 600 cycles. It should be noted that the nominal capacity of batteries is 200 mAh. And the profile is CC 0.5 C to 2.8 V 0.05 C for charging, and CC 0.5 C to 1.5 V for discharging. 

1. A quasi-solid-state electrolyte composition for a secondary Li battery comprising: (a) three-dimensionally ordered macroporous metal-organic framework materials (3DOM-MOFs); (b) a polymer electrolyte; (c) a liquid organic electrolyte; and (d) a lithium salt.
 2. The quasi-solid-state electrolyte composition of claim 1, wherein weight percentages of the 3DOM-MOFs are in a range of 10%-70%, the weight percentages of the polymer electrolyte are in a range of 5%-20%, the weight percentages of the liquid organic electrolyte are in a range of 0.01%-0.1%, and the weight percentages of the said lithium salt are in a range of 5%-19.9%.
 3. The quasi-solid-state electrolyte composition of claim 1, wherein the 3DOM-MOFs is selected from at least one of 3DOM-PCN-601, 3DOM-ZIF-8, 3DOM-ZIF-67, 3DOM-ZIF-68, 3DOM-ZIF-69, 3DOM-ZIF-70, 3DOM-ZIF-78, 3DOM-ZIF-81, 3DOM-ZIF-82, 3DOM-ZIF-95, 3DOM-ZIF-100, [{Fe₃(μ₃-O)(bdc)₃}₄{Co₂(na)₄(LT)₂}₃] and JUC-1000.
 4. The quasi-solid-state electrolyte composition of claim 1, wherein the polymer electrolyte is selected from at least one of Polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and their derivates.
 5. The quasi-solid-state electrolyte composition of claim 1, wherein the liquid organic electrolyte is selected from at least one of tetraethylene glycol dimethyl ether (TEGDME), 1,2-Dimethoxyethane (DME), Diethylene glycol dimethyl ether (DG), tetraglyme (TG), 1,3-dioxolane (DOL), Tetrahydrofuran (THF), and ethyl methanesulfonate (EMS).
 6. The quasi-solid-state electrolyte composition of claim 1, wherein the lithium salt is selected from at least one of LiPF₄, LiBF₄, LiClO₄, LiAsF₆, LiBOB, LiODFB, LiCF₃SO₃, LiN(SO₂CF₃)₂.
 7. The quasi-solid-state electrolyte composition of claim 1, wherein a type of the 3DOM-MOFs is one type or two types.
 8. The quasi-solid-state electrolyte composition of claim 1, wherein a weight percentage of the 3DOM-MOFs ranges from 1.5% to 50%.
 9. The quasi-solid-state electrolyte composition of claim 1, wherein the polymer electrolyte comprises pure PEO or a mixture of PEO and another different polymer.
 10. The quasi-solid-state electrolyte composition of claim 1, wherein a weight percentage of the 3DOM-MOFs ranges from 5% to 10%.
 11. The quasi-solid-state electrolyte composition of claim 1, wherein a type of the liquid organic electrolyte is one type or two types.
 12. The quasi-solid-state electrolyte composition of claim 1, wherein a weight percentage of the liquid organic electrolyte ranges from 0.02% to 0.1%.
 13. The quasi-solid-state electrolyte composition of claim 1, wherein a type of the lithium salt is more than two types.
 14. The quasi-solid-state electrolyte composition of claim 1, wherein a weight percentage of the lithium salt ranges from 5% to 15%. 